Manufacture of wood-pulp.



J. G. W. STANLEY. MANUFACTURE or WQOD PULP.

APPLICATION FILED DEG.14.1909

Patented Aug. 23, 1910.

In uek 2'0 Join C M 5/4/19 5 J Zdafizeues,

is J far/1 UNITED STATES JOHN C. W. STANLEY, OF SANTA CRUZ, CALIFORNIA, ASSIGNOR OF ONE-HALF TO DANIEL H. MCEWEN, 0F BURLINGAME, CALIFORNIA, AND ONE-HALF 1'0 FRANK 1B. VIILSON, OF SAN FRANCISCO, CALIFORNIA.

MANUFACTURE OF WOOD-P171315.

Specification of Letters letent.

Patented Aug. 23, 1910.

To all whom it may concern:

Be it known that I, JOHN CHARLES WIL- LIAMS STANLEY, a subject of the King of England, residing at Santa Cruz, in the county of Santa Cruz and State of California, have invented new and useful Improvements in the Manufacture of Wood- Pulp, of which the following is a' specification.

My invention relates to the manufacture of pulp for paper-making purposes.

The object of this invention is the manufacture of pulp suitable for making paper from wood, such as redwood, cedar, fir, cypress, yellow pine, and like more or less resinous trees, which has not been found possible on a commercial scale by present methods used for treating such woods as spruce, hemlock and poplar.

The drawing represents a machine suitable for carrying out the process.

In the practice of the invention, the process is carried out in the following manner:

The tree is cut down and sawed into boards about four feet long and about four inches thick, and the branches into about four feet lengths, dependent somewhat on the size of the apparatus used for treating the wood. Preferably I use the refuse from I the lumber mills, such as outside slabs, edgings and short ends. The prepared wood is reduced to splinters in what is known as a hog, a machine used in lumber mills for breaking up wood for steam boiler fuel. The hog, represented at 2, will produce a product of irregular sizes, and I find it desirable to separate by screening through a cylinder 3 of half-inch mesh, the small splinters and sawdust which are treated separately. For converting the large splinters into pulp I employ a tank or vat 4 of any desired size, shape and material. About three inches from the bottom is placed a plate 5 perforated with holes of quartermch diameter. Under this plate is a valve 6, also a steam coil 7 for heating the contents of the vat. About'three inches from the top of the tank is a hinged perforated plate 8. Within this tank the splintered wood is soaked in a ten Baum solution of caustic soda which is kept at a uniform temperature of about 200 Fahrenheit by the steam coil 7. The tank is filled with as opened and the liquor drained into a digester 9 in which the soaked Wood from Vat 4 is cooked under steam pressure.

In practice, the digester is of ordinary boiler plate sufiiciently strong to stand eighty pounds working pressure. A convenient size of digester would be about thirtyfive feet long and eight feet in diameter, having a cone at one end with a manhole door 10 and a steam valve 11. For convenience the digester is suspended centrally by trunnion bearings 12 through which steam is conveyed through a coil of pipes 13 placed in the bottom and along one side of the digester. The digester is placed in a vertical position for filling with the liquor from the soaking tank. After this liquor has been heated by the steam in pipes 13 to boiling point, the soaked wood is then removed from the vat and placed in this boiling liquor in the digester. The manhole door 10 is then placed in position and closed, and the pressure in the digester raised to approximately eighty pounds by admitting steam through the valve 11. The boiling temperature and high pressure is maintained gester. During the cooking the digester remains in a substantially horizontal position. To empty it, after cooking, the manhole is opened and the digester inverted, whereupon the entire contents of the digester, liquor and wood pulp, are discharged into a suitable pit 14. This pit is preferably coneshaped, as here shown, and provided with a series of refrigerating coils 15 for cooling the cooked solution and fiber. Cold air is blown into the mass in pit 14 through the coils 15 to cool the contents of the pit to about 100 Fahrenheit.

I find that by allowing the cooked wood to remain in the solution in which ithas been boiled, until cooled to about 100 Fahrenheit, that the fiber becomes exceedingly tough, giving it a silky appearance.

covery of the soda remaining in the wood.

The crushed material is then placed in a tank 19 .and washed so as to remove any remaining traces of soda. The washed fiber is thence carried by suitable means, as the conveyer 20, to a pulp-press 29, where, after pressing, the material is ready for making into paper.

The liquor strained oil by the screen 17 is treated in any suitable manner to recover the soda and various by-products resulting from the various preceding steps in the process. 7

The treatment of the wood in vat 4 by caustic soda, and for the period of time mentioned, is to effect a certain disintegration of the fibers, and to cause a gradual absorption or dissolution of the resins. The resins are gradually dissolved by the caustic soda under the action of heat, so as to open up the pores of the wood and preparethe Wood for future treatment. The wood when it comes out of the vat is more or less spongy and porous. The cooking of the wood in its own juices and original caustic solution in the digester, results in a further and final disintegration of the wood, and makes it soft and fibrous; separating the non-fibrous from the fibrous portions. The subsequent partial cooling of the cooked material in its liquor in vat 14 permits the gelatinous gums to adhere to the fibers and not be lost as they would be if the'liquor was drawn off immediately from the fiber when the hot digester was first emptied. By allowing the liquor to cool slowly, these gums which are comparatively insoluble in cold water, adhere to the fiber and act as a size to the finished paper, thereby enhancing the value of the pulp.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. The process of making wood pulp which includes soaking the wood in a hotcaustic soda solution, subse uently boiling the wood in the solution un er pressure in a closed vessel, cooling the wood product in the liquor in which it has been boiled, and subsequently separating the wood product from the liquor.

2. The process of manufacturing wood pulp which includes soaking the wood in a hot caustic soda solution, straining the seams liquor from the wood into a digester, raising the temperature to boiling point, adding the previously soaked wood, and cooking in the digester at a pressure in excess of atmospheric pressure until the wood becomes thoroughly disintegrated, and allowing the wood product to be cooled while in the liquor in which it was boiled.

3. The process of manufacturing wood pulp which includes soaking the wood in a hot caustic soda solution, straining the liquor from the wood into a digester, raising the temperature to boiling point, adding the previously soaked wood and cooking in the digester at a pressure in excess of atmospheric pressure until the wood becomes thoroughly disintegrated, relievin the pressure in the digester and gradually cooling the wood product in its liquor, and subsequently separating the liquor from the wood.

4. The process of manufacturing pulp which includes soaking the wood in a suitable alkaline solution, then cooking the soaked wood in its solution in a closed vessel at approximately boiling temperature and at approximately eighty ounds pressure until the wood becomes isintegrated, and cooling the wood product in its liquor.

5. The process of manufacturing pulp which includes soaking the wood in a suitable alkaline solution, then cookin the soaked wood in its solution in a close vessel at approximately boiling temperature and at approximately eighty pounds pressure until the wood becomes disintegrated, gradually cooling the disintegrated wood product in its liquor to about 100 Fahrenheit, and finally separating the wood prod- V not from its solution.

6. The process of manufacturing pulp which includes soaking the wood in a suitable alkaline solution, then cooking the soaked wood in its solution in a closed vessel at approximately boiling temperature and atapproximately eighty ounds pressure until the wood becomes isintegrated, gradually cooling the disintegrated wood product in its liquor to about 100 Fahrenheit, separating the wood roduct from its solution, crushing the pn p so separated, washing it, and then running it through suitable pulp pressers.

7. The method of manufacturing wood' pulp which comprehends disintegrating the wood into large pieces, soaking the wood completely submerged in a solution of approximately ten Baum caustic soda at a temperature of approximately 200 Fahrenheit, straining the liquor from the wood into a digester, raising the temperature to approximately 212 Fahrenheit, adding t e wood and cooking in the digester at approximately eighty pounds pressure for approximately eight hours, and then cooling the disintegrated wood in its liquor.

8. The method of manufacturing wood pulp which comprehends disintegrating the wood into large pieces, soaking the wood completely submerged in a solution of approximately ten Baum caustic soda at a temperature of approximately 200 Fahrenheit, straining the liquor from the wood into a digester, raising the temperature to approximately 212 Fahrenheit, adding the wood and cooking in the digester at approximately eighty pounds pressure for approximately eight hours, discharging the cooked material and liquor into a vat and cooli the same to a proximatel a temperature i 100 'Fahren eit, and tile liquor from the wood product.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

JOHN G. W. STANLEY.

Witnesses:

CHARLES EDELMAN, W. DE SAMSCUM.

n straining the 15 

